Method for gas extraction alternating oscillating pulse high energy gas extraction with thermal injection

摘要

Disclosed is a method for gas extraction involving alternation of oscillating pulse high energy gas extraction with thermal injection. First, high energy gas fracturing technology is used to form a fracture network in a thermal injection borehole (3), then a steam generator (12) is used to force high-pressure, cyclically temperature-changing steam into said borehole (3); the steam passing through a spinning oscillating-pulse jet nozzle (6) forms an oscillating superheated steam, alternatingly impacting and heating the coal body. The present method is applicable to managing gas extraction from microporous, low-permeability, high-adsorption coal seam areas, overcoming the limitations of simple permeability-increasing techniques; using high energy gas fracturing of the coal body increases the disturbance range around a single well, forming a fracture network that provides channels for passage of the superheated steam, while oscillating changes in steam temperature and pressure also promote crack propagation and perforation of the coal body; the combined effect of alternation of the two enhances gas desorption and extraction efficiency.